The invention concerns frequency effect electronic devices.
Changing the frequency of a signal is known using a non-linear element, to which the initial signal F1 and a modulating signal f2 are applied. Acting as a mixer or multiplier, the non-linear element provides modulation products of the form (p*F1)+(q*f2), where p and q are two positive or negative integers. The desired modulation product is extracted by filtering. Although they perform a multiplication, these devices are sometimes referred to as "frequency translators", since they make it possible to obtain, notably, F1+f2.
The invention more particularly concerns the conventional frequency translators which directly provide the addition or translation F1+f2, by multiplication, but without requiring filtering.
To implement such conventional frequency translators, a so-called "variable delay" technique can be used, this delay being arranged to correspond to a phase shift increasing linearly with time. This technique uses the fact, since the frequency is the derivative of the phase with a factor of approximately 1/2.pi., the output signal has additional frequency. This variable delay can be implemented in analog form or in digital form. However, these so-called "serrodyne" techniques used currently are quite difficult to implement as regards the hardware.
Furthermore, these techniques require components whose size is relatively large.